Start Developing, How to compile

I need some advice on how to compile everything, I did not find anything in detail in the wiki.

I checked out the code (12.4), but maven failed with
"Non-resolvable parent POM for org.xwiki.platform:xwiki-platform:12.5-SNAPSHOT: Could not find artifact org.xwiki.commons:xwiki-commons-pom:pom:12.5-SNAPSHOT "…
Does it need any additional setup?

Thanks Al

See and especially the part about setting up your settings.xml.

perfect, thx!